David Cameron has admitted there "aren't enough" moderate Syrian rebels taking on Islamic State (Isis) in Syria and President Bashar al-Assad. The prime minister made the somewhat surprising remark during a hearing before a group of MPs on 12 January.

The Conservative leader was being questioned by the House of Commons' Liaison Committee, which is made up of 32 committee chairs of the lower chamber, over his claim that "70,000" moderate rebels operated in Syria.

The figure came amid fears UK military intervention in the war-torn nation could play into the hands of IS (Daesh). The claim also crucially proceeded MPs' decision to vote for British air strikes on IS targets in Syria.

If you are arguing – there aren't enough, we need to build them up – yes we do, I agree. You have to start somewhere

- David Cameorn

Dr Julian Lewis, the Conservative chairperson of the Defence Committee, questioned Cameron over the figure in November 2015. The New Forest East MP was able to grill the prime minister on the same issue during the Liaison Committee's hearing.

"Yes, some of the opposition forces are Islamists, some of them a relatively hard-line Islamists and some of them are what we would call more secular democrats. They are groups like al-Nusra Front who we wouldn't work with, who we condemn," Cameron replied.

"But if you are arguing – there aren't enough, we need to build them up – yes we do, I agree. You have to start somewhere. Every day we don't support moderate forces, they are hit by Assad."

Liaison Committee chairman Andrew Tyrie also pressed the prime minister on the matter. He suggested Cameron could gain extra credibility by revealed where the "70,000" figure is sourced from. But Cameron only went as far to say that the number was from the Joint Intelligence Committee and asked the MPs who had been fighting Assad's forces since the Syrian civil war began in 2011.

Columb Strack, a senior Middle East analyst at IHS, had previously told IBTimes UK that the number of moderate rebels in Syria depends on your definition of "Islamist".

"I'd say the 70,000 figure is roughly in the right ballpark in terms of the number of rebels that would be willing to enter into a dialogue including Western and other countries over the future of Syria," he said.

"However, many of these must still be considered Islamist in that their ultimate goal is to establish a Sunni Islamic state. Practically all of the key players among the rebel factions in northern Syria [eg Ahrar al-Sham, Jaysh al-Islam, Jabhat al-Nusra] are Islamists to varying degrees. Groups operating in the south of the country, particularly those under the FSA's Southern Front [about 35,000 fighters] are generally more secular."